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Species of the subgenus Symplecta Meigen with Arctic, or at least partly Arctic, distributions are revised. Five species are redescribed: S. (S.) novaezemblae (Alexander), S. (S.) scotica (Edwards), S. (S.) mabelana (Alexander), S. (S.) sheldoni (Alexander), and S. (S.) horrida (Lackschewitz). Two new species are described: S. (S.) edlundaesp. nov. (Northwest Territories and Yukon, Canada) and S. (S.) echinatasp. nov. (eastern Siberia, Russia). Five new synonyms are proposed: Erioptera (S.) sunwapta Alexander and Helobia intermedia Lackschewitz = S. (S.) scotica; Erioptera (S.) platymera Alexander = S. (S.) mabelana; S. (S.) rotundiloba Podenas and Gelhaus = S. (S.) sheldoni; and Erioptera (Psiloconopa) chaetophora Alexander = S. (S.) horrida. Symplecta (Symplecta) scotica and S. (S.) mabelana are restored as full species from subspecies rank. Symplecta (Symplecta) horrida, previously placed in Erioptera (Mesocyphona) Osten Sacken, is transferred to Symplecta s.s. The distinctions between S. (S.) cana (Walker) and S. (S.) hybrida (Meigen) are clarified and the sympatric and syntopic occurrences of these species are documented. A key to the species treated, and illustrations of both male and female terminalia, are provided and the distribution of each species is outlined.
The ash leaf cone roller, Caloptilia fraxinella (Ely), is a leaf-mining moth that has recently become a significant pest of horticultural ash, Fraxinus L., species in communities throughout the western prairie provinces of Canada. The study examines the spatial and temporal within-host distribution of immature stages of C. fraxinella on green ash, Fraxinus pennsylvanica Marsh. Female C. fraxinella showed a preference for oviposition sites in the lower canopy and on the south side of the tree at the beginning and middle of the 3-week oviposition period, respectively, but no preference at the end of the period. Oviposition was constrained temporally and occurred mainly just after green ash bud flush. Immature stages were sampled throughout the growing season, and measured widths of larval head capsules showed five instars. Fourth-instar larvae disperse from the mined leaflet to a new leaflet, roll it into a cone, and pupate. Neither canopy height nor ordinal direction affected the position of larvae in the canopy, but numbers of immature stages varied by tree within a site. Female and male moths eclose from rolled leaf cones synchronously throughout the emergence period. The study provides some of the basic biological information required to design an integrated pest management program to target this emerging pest of horticultural ash trees.
Sticky-band trapping experiments were undertaken in 2003–2006 to examine the host-seeking behaviour of the emerald ash borer, Agrilus planipennis Fairmaire, in woodlots in southwestern Ontario, Canada. The female proportion of A. plannipennis emerging from host logs ranged from 0.414 to 0.582. Landings on sticky-band traps varied more with the female proportion, ranging from 0.392 to 0.889, with the majority in the upper range, suggesting behavioural differences between the sexes. Correlations between landing density and tree size measured as diameter at breast height were positive or showed no relationship. In some locations more beetles were captured on the south side of the tree than on the north side; however, there was no difference between these cardinal directions at other locations. Numbers of captured beetles were never significantly greater on the north side of boles. We observed greater landing densities of adults of both sexes on traps on trees along the edges of woodlots than on trees within the woodlots. When given a choice under natural conditions, beetles landed almost exclusively on host trees (Fraxinus pennsylvanica Marsh. (Oleaceae)) rather than on other common trees species (Carya ovata (Mill.) K. Koch (Juglandaceae), Tilia americana L. (Tiliaceae), and species of Acer L. (Aceraceae)) found in the same woodlots. Our data suggest that A. planipennis make host-selection decisions while in flight rather than landing randomly. Implications for monitoring A. plannipennis using sticky-band traps and understanding its host-seeking behaviour are discussed.
In a trapping study conducted in the experimental research forest of the Tohoku Research Center, Morioka, Honshu, Japan, we investigated the effect of heterospecific pheromone on pheromonal attraction of male Japanese gypsy moth, Lymantria dispar japonica (Motschulsky), and male pink gypsy moth, L. mathura Moore (Lepidoptera: Noctuidae: Lymantriinae). Traps baited with synthetic pheromone of L. d. japonica ((7R,8S)-cis-7,8-epoxy-2-methyloctadecane = ( )-disparlure (100 µg)) or L. mathura ((9R,10S,3Z,6Z)-cis-9,10-epoxynonadecadiene = ( )-mathuralure (20 µg) and (9S,10R,3Z,6Z)-cis-9,10-epoxynonadecadiene = (-)-mathuralure (80 µg)) attracted male L. d. japonica or L. mathura, respectively. Traps baited with synthetic pheromone of both species captured significantly fewer male L. mathura than traps baited solely with synthetic L. mathura pheromone. Numbers of male L. d. japonica captured in traps baited with ( )-disparlure were unaffected by the addition of L. mathura pheromone. ( )-Disparlure is a behavioral antagonist to pheromonal attraction of male L. mathura, whereas male L. d. japonica are indifferent to the presence of synthetic L. mathura pheromone.
Biodiversity and evolution / Biodiversité et évolution
Pseudips mexicanus (Hopkins) is a secondary bark beetle native to western North and Central America that attacks most species of pine (Pinus L. (Pinaceae)) within its range. A pair of life-history studies examined P. mexicanus in other host species, but until now, no work has been conducted on lodgepole pine (Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson). Pseudips mexicanus in lodgepole pine was found to be polygynous. Galleries were shorter, offspring smaller, and the eggs laid per niche and the potential progeny fewer than in populations from California and Guatemala. Development from the time of female attack to emergence of adult offspring took less than 50 days at 26.5 °C, and the accumulated heat required to complete the life cycle was determined to be 889.2 degree days above 8.5 °C, indicating that in the northern portion of its range P. mexicanus is univoltine. Determination of these life-history traits will facilitate study of interactions between P. mexicanus and other bark beetle associates in lodgepole pine.
Periodic sweep-net sampling and capitula sampling were conducted between April and October 2007 to determine the seasonal phenology of Urophora quadrifasciata (Meigen) (Diptera: Tephritidae) on spotted knapweed, Centaurea stoebe subsp. micranthos (Gugler) Hayek (Asteraceae), in the Arkansas Ozarks of the United States of America. Urophora quadrifasciata produces up to three generations in Arkansas, rather than being bivoltine as in the northern United States of America. The first, second, and third generations of U. quadrifasciata reached peak adult numbers around 26 May, 29 June, and 27 July, respectively. Males tended to emerge earlier than females but the female:male ratio was approximately 1:1 for most of the season. The majority of the offspring of the three generations emerged between June and October, while approximately 38% entered diapause and emerged as adults in April–June of the following year; 3.4 ± 0.1 (mean ± SE) (range 1–12) flies emerged from each infested capitulum. The absence of other, competing knapweed biological control agents as well as very low rates of parasitism, mild weather conditions, and a longer knapweed growing season likely contributed to the adaptation and establishment of U. quadrifasciata on spotted knapweed in Arkansas.
The only known Canadian population of the white flower moth, Schinia bimatris Harvey, a federally listed endangered species, was rediscovered in 2003 in the dune area of Spruce Woods Provincial Park and Canadian Forces Base Shilo in Manitoba. Little is known about the biology or habitat requirements of this moth in North America. The dune area in Manitoba was surveyed for adult and immature stages of the species during July 2007 using light traps and daytime visual searches. A detailed vegetation survey was also completed in areas where moths were active. Whereas individuals caught in light traps were predominantly males, both females and males were observed to be very active during daylight hours. This is the first record of diur-nal activity of the white flower moth in Canada. Adults were observed flying above dune crests and also resting on vegetation between open dunes. Although the current population appears robust, given the number of adults observed, a previous population approximation of up to 5000 individ-uals may be an overestimate because sand-dune habitat is limited. We were unable to locate im-mature stages or determine which host plant(s) were utilized by larvae.
The effects of the horticultural oil Purespray Green on oviposition behaviour and egg development in the obliquebanded leafroller, Choristoneura rosaceana (Harris), were investigated through dual-choice and no-choice bioassays and topical applications of oil to developing eggs. A residual 2% (v/v) oil spray on wax-paper and apple-leaf substrates significantly reduced both the number of eggs laid and egg survival in no-choice assays; however, this effect diminished 3 days after treatment. In dual-choice assays, females laid significantly fewer eggs on oil-treated apple leaves than on control leaves, but laid equal numbers of eggs on the oil-treated wax paper and the untreated wax-paper controls. Topical application of oil caused significant dose-dependent mortality of both newly laid eggs and eggs just before hatch, and these two egg stages were equally susceptible to the oil. Topical application of 2% oil caused >99% egg mortality. Our data indicate that gravid female C. rosaceana can assess and reject oil-sprayed surfaces and that the oil can kill eggs through both contact toxicity and suffocation. These characteristics suggest that highly purified horticultural oils like Purespray Green could play a role in an integrated pest management program for this important pest species.
In view of the increasing use of plant proteins as valuable alternatives to chemical insecticides, the susceptibility of pea aphids, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), to three purified mannose-binding plant lectins was determined in an artificial-diet bioassay. The insecticidal activities of a new lectin, APA (Allium porrum L. (Liliaceae) agglutinin) from garden leek, were compared with those of GNA (Galanthus nivalis L. (Liliaceae) agglutinin) from snowdrop and ASA (Allium sativum L. agglutinin) from cultivated garlic. GNA and ASA showed acute toxicity to first-instar nymphs; LC50 values for GNA and ASA were 350 and 700 µg/mL, respectively. With APA, mortality was scored only at high doses. In chronic experiments, however, lower doses significantly reduced survival and fecundity of adults (P < 0.05). Aphids fed a diet containing APA at 100, 500, and 750 µg/mL showed a significant delay in reaching adulthood and no aphids survived beyond 19 days of development. The data support the potential application of APA in the integrated management of insect pests.